At present, three-dimensional image rendering is a relatively expensive and time-consuming process. Typically, a three-dimensional image is an image of three-dimensional models in a computer-defined three-dimensional world viewed from a viewpoint within the three-dimensional world. Many times, the three-dimensional world includes a number of three-dimensional models that are spread throughout to create a virtual environment. Generally, an image of the three-dimensional models in the three-dimensional world can only view a portion of the three-dimensional models in the three-dimensional world. Assume a three-dimensional world includes dozens of three-dimensional models and an image to be generated is a perspective view that includes only four of the dozens of three-dimensional models. If a three-dimensional engine is required to render all of the dozens of three-dimensional models prior to generating an image that includes only four of the three-dimensional models, image rendering costs and processing time are unacceptably high. The answer to this rendering problem is to determine what three-dimensional models are to appear in the field of view of the to-be-generated image (based on a desired viewpoint) and render only those models that were determined to be within the field of view. Models that will not appear in the displayed output are not rendered, thereby minimizing rendering costs and processing time.
Markup documents generated by a markup document processing component, such as an HTML image renderer of an operating system utility, as described in co-pending patent application Ser. No. 09/105,831, are rendered and stored in texture image files that are then mapped to three-dimensional models by a three-dimensional engine. Even though the three-dimensional engine understands how to save processing time and costs by only rendering those three-dimensional models that appear within the field of view, the markup document processing component still renders all markup documents that are assigned to textures on all of the three-dimensional models within the three-dimensional world.
The present invention is directed to overcoming the foregoing and other disadvantages. More specifically, the present invention is directed to providing a method and apparatus for making a markup document processing component more efficient when rendering markup documents as texture on three-dimensional models.